Inkjet printers work by dropping controlled amounts of ink on a page, using one of three main technologies: thermal drop-on-demand, piezoelectric and continuous. Worldwide, the four major inkjet players are Canon, Hewlett-Packard, Epson and Lexmark.
Lord Kelvin first patented the continuous inkjet method in 1867, but it took nearly a century for technology to catch up with the idea. The continuous method uses electrically charged droplets to coat the page and is wasteful of ink, more suited to industry than consumers. In 1951, Siemens created the first commercial continuous inkjet devices--medical strip chart recorders.
In the late 1960s, researcher R.G. Sweet's experiments with continuous inkjet printing led to the first commercial inkjet printers, the A.B. Dick, VideoJet and Mead DIJIT. IBM took out a license on the technology and released the first peripheral, the IBM 4640 Ink Jet, in 1976.
By the mid-1970s, developers were predicting that inkjets would replace dot matrix printers. However, they still did not know how to control ink output enough to allow printing on paper.
In 1977, Siemens invented thermal or drop-on-demand printing, the method used in most inkjets today. Heat pushes out drops of ink only when needed, but there was still a problem with the inkjets clogging. The same year, Canon engineer Ichiro Endo discovered that water-based inks worked better.
Hewlett-Packard and Canon solved the inkjet problem within a year of one another. In 1984, HP introduced its first inkjet printer, the HP Thinkjet. A year later, Canon released the Canon BJ-80, the world's first bubble jet printer.
HP's DeskJet, the company's first mass-market inkjet printer, debuted in 1988 at a price of $1,000!
Lexmark International was originally owned by IBM, which sold Lexmark to a private investment group, Clayton, Dubillier and Rice. Financier Martin Dubillier streamlined the company and made it competitive as inkjet technology blossomed. In 1992, Lexmark released its first Lexmark inkjet.
Epson developed the micro piezo method in 1993, and released the Epson MJ-500 inkjet printer (Epson Stylus 800). While the other three main players continue with drop-on-demand, Epson remains true to its own invention. In 1994, it released the Epson Stylus Color (P860A), the first high-resolution (720 dpi) color printer.
The 1990s saw the development of multifunction devices that incorporated printers, scanners and faxes into one machine, as well as improvements in color printing.
Inkjet printers continue to improve, popular because they are affordable. Models are becoming smaller, quicker, quieter and more efficient.
Industrial models, too, continue to improve. In November 2008, the fastest cut-sheet inkjet printer was the RISO HC5500. It could print 120 full-color sheets per minute.
- Scientific Examination of Questioned Documents; Jan Seaman Kelly, Brian S. Lindblom, editors; 2006